Focus-adjustable liquid crystal eyeglasses

Abstract

Described are examples of adjustable focus glasses formed using liquid crystal. A pair of adjustable focus glasses can include a frame and two lenses arranged on the frame. In some examples, at least one of the two lenses is a lens assembly that includes a plano-concave lens, a Fresnel lens, and a liquid crystal layer between the plano-concave lens and the Fresnel lens. The plano-concave lens includes a planar surface and an opposing concave surface. The Fresnel lens includes a Fresnel surface and an opposing convex surface. The planar surface and the Fresnel surface face the liquid crystal layer. The focus position of the lens assembly can be adjusted through changing the refractive index of the liquid crystal layer, using appropriate control signals from an electronic controller. This conveniently allows the adjustable focus glasses to be multi-purpose and suitable for correcting both myopia and hyperopia.

What is claimed is: 
     
       1. A lens assembly comprising:
 a plano-concave lens including a planar surface and a concave surface opposite the planar surface; 
 a Fresnel lens including a Fresnel surface and a convex surface opposite the Fresnel surface; 
 a liquid crystal layer between the plano-concave lens and the Fresnel lens, wherein the planar surface and the Fresnel surface face the liquid crystal layer, and 
 a sealing structure adapted to seal the liquid crystal layer, wherein the sealing structure is located near an edge of the plano-concave lens and an edge of the Fresnel lens, 
 wherein: 
 the sealing structure comprises a convex ring and a groove; 
 the convex ring is configured to mate with the groove; 
 the convex ring is located on one of the plano-concave lens or the Fresnel lens; and 
 the groove is located on the other of the plano-concave lens or the Fresnel lens. 
 
     
     
       2. The lens assembly of  claim 1 , further comprising:
 a first indium tin oxide (ITO) layer; and 
 a second ITO layer, wherein the liquid crystal layer is between the first ITO layer and the second ITO layer. 
 
     
     
       3. The lens assembly of  claim 2 , wherein the first ITO layer is electroplated onto the planar surface of the plano-concave lens, and wherein the second ITO layer is electroplated onto the Fresnel surface of the Fresnel lens. 
     
     
       4. The lens assembly of  claim 2 , further comprising:
 an insulating film between the first ITO layer and the second ITO layer, wherein the insulating film is formed of an electrically insulating material. 
 
     
     
       5. The lens assembly of  claim 4 , wherein the insulating film comprises silicon dioxide. 
     
     
       6. The lens assembly of  claim 1 , wherein the plano-concave lens and the Fresnel lens have the same refractive index. 
     
     
       7. The lens assembly of  claim 1 ,
 wherein the sealing structure comprises one or more sealing elements located in a gap between the plano-concave lens and the Fresnel lens. 
 
     
     
       8. The lens assembly of  claim 7 , wherein the sealing structure comprises an ultraviolet (UV) sealant. 
     
     
       9. The lens assembly of  claim 1 , wherein the liquid crystal layer has a first state and a second state, and wherein the liquid crystal layer has a different refractive index in the first state than in the second state. 
     
     
       10. The lens assembly of  claim 9 , wherein the liquid crystal layer is configured to be in the first state when subjected to a first voltage, and wherein the liquid crystal layer is configured to be in the second state when subjected to a different voltage or not subjected to any voltage. 
     
     
       11. The lens assembly of  claim 9 , wherein the liquid crystal layer is configured to maintain a particular state after the liquid crystal layer is no longer being subjected to a voltage that caused the liquid crystal layer to be in the particular state. 
     
     
       12. A pair of adjustable focus glasses comprising:
 a frame; 
 a first optical lens; and 
 a second optical lens, wherein the first optical lens and the second optical lens are mounted on the frame, and wherein at least one of the first optical lens or the second optical lens is a lens assembly that comprises: 
 a plano-concave lens including a planar surface and a concave surface opposite the planar surface; 
 a Fresnel lens including a Fresnel surface and a convex surface opposite the Fresnel surface; 
 a liquid crystal layer between the plano-concave lens and the Fresnel lens, wherein the planar surface and the Fresnel surface face the liquid crystal layer; and 
 a sealing structure adapted to seal the liquid crystal layer, wherein the sealing structure is located near an edge of the plano-concave lens and an edge of the Fresnel lens, 
 wherein: 
 the sealing structure comprises a convex ring and a groove; 
 the convex ring is configured to mate with the groove; 
 the convex ring is located on one of the plano-concave lens or the Fresnel lens; and 
 the groove is located on the other of the plano-concave lens or the Fresnel lens. 
 
     
     
       13. The adjustable focus glasses of  claim 12 , wherein the lens assembly further comprises:
 a first indium tin oxide (ITO) layer; and 
 a second ITO layer, wherein the liquid crystal layer is between the first ITO layer and the second ITO layer. 
 
     
     
       14. The adjustable focus glasses of  claim 13 , wherein the first ITO layer is electroplated onto the planar surface of the plano-concave lens, and wherein the second ITO layer is electroplated onto the Fresnel surface of the Fresnel lens. 
     
     
       15. The adjustable focus glasses of  claim 13 , wherein the lens assembly further comprises:
 an insulating film between the first ITO layer and the second ITO layer, wherein the insulating film is formed of an electrically insulating material. 
 
     
     
       16. The adjustable focus glasses of  claim 15 , wherein the insulating film comprises silicon dioxide. 
     
     
       17. The adjustable focus glasses of  claim 12 , wherein the plano-concave lens and the Fresnel lens have the same refractive index. 
     
     
       18. The adjustable focus glasses of  claim 12 , wherein:
 the sealing structure comprises one or more sealing elements located in a gap between the plano-concave lens and the Fresnel lens. 
 
     
     
       19. The adjustable focus glasses of  claim 18 , wherein the sealing structure comprises an ultraviolet (UV) sealant. 
     
     
       20. The adjustable focus glasses of  claim 12 , wherein the liquid crystal layer has a first state and a second state, and wherein the liquid crystal layer has a different refractive index in the first state than in the second state. 
     
     
       21. The adjustable focus glasses of  claim 20 , wherein the liquid crystal layer is configured to be in the first state when subjected to a first voltage, and wherein the liquid crystal layer is configured to be in the second state when subjected to a different voltage or not subjected to any voltage. 
     
     
       22. The adjustable focus glasses of  claim 20 , wherein the liquid crystal layer is configured to maintain a particular state after the liquid crystal layer is no longer being subjected to a voltage that caused the liquid crystal layer to be in the particular state. 
     
     
       23. The adjustable focus glasses of  claim 12 , further comprising:
 a power source; and 
 an electronic controller connected to the power source, wherein the power source and the electronic controller are arranged on the frame, and wherein the electronic controller is configured to control a state of the liquid crystal layer in at least one lens assembly by causing a voltage to be supplied to the at least one lens assembly.